Evidence-based management of preterm labor: The role of tocolytics and antibiotics

John M. Thorp, Katherine E. Hartmann

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Preterm labor is often a prelude to early births and the significant burdens of infant morbidity and mortality. Treatment consists of bed rest, hydration, pharmacological interventions, and combinations of these. Tocolytics to stop uterine contractions and antibiotics to eradicate occult infections are 2 treatments commonly given to prevent preterm birth. The objectives of this review were (1) to evaluate the evidence on the benefits and harms of 5 classes of tocolytic therapy for treating uterine contractions related to preterm labor: beta-mimetics, calcium channel blockers, magnesium, nonsteroidal anti-inflammatory agents, and ethanol; and (2) to evaluate the evidence regarding the usefulness of antibiotics for treating preterm labor. Data sources included reports of randomized controlled trials and other study designs in English, French, and German identified from searches of MEDLINE, EMBASE, specialized databases, bibliographies of review articles, unpublished literature, and discussions with investigators in the field. Studies on women with preterm labor between 1966 and February 1999 met our inclusion criteria. Using dual review, we abstracted study design and masking; definitions of preterm labor and pregnancy outcome; patient inclusion and exclusion characteristics; patient demographic characteristics; drugs and cointerventions; and numerous birth, maternal, and neonatal outcome measures. We graded the quality of the individual articles and the strength of the evidence for tocolytic and antibiotic benefit. Of the 256 tocolytic-related articles evaluated, we abstracted data from 60 first-line and 15 maintenance studies. Of these, 16 first-line and 8 maintenance studies met more stringent requirements for meta-analyses. Studies of first-line tocolysis (graded fair) revealed a mixed outcome pattern with small improvement in pregnancy prolongation and birth at term relative to placebo. Data were insufficient to show a beneficial effect on neonatal morbidity or mortality. Ethanol was less beneficial than, and beta-mimetics were not superior to, other tocolytic options. Maintenance tocolytics (graded poor) showed no improvements in birth or infant outcomes relative to placebo; these results were confirmed through meta-analysis. In contrast to other tocolytic treatments, maternal harms from beta-mimetics were graded high; all tocolytics were graded low for short-term neonatal harms. We abstracted antibiotic data from 14 randomized trials and 1 observational study. Of these studies, 13 met requirements for meta-analysis. Meta-analysis demonstrated a mixed outcome pattern with small improvements in pregnancy prolongation, estimated gestational age at birth, and birth weight. Data were insufficient to show a beneficial effect on neonatal morbidity or mortality. Management of uterine contractions with first-line tocolytic therapy can prolong gestation. Among the tocolytics, however, beta-mimetics appear not to be better than other drugs, and they pose significant potential harm for mothers; ethanol remains an inappropriate therapy. Continued maintenance tocolytic therapy has apparently little or no value. Treatment of preterm labor with antibiotic therapy can prolong gestation. The benefits of antibiotics are small, and there is considerable uncertainty about the optimal agent, route, dosage, and duration of therapy.

Original languageEnglish
Pages (from-to)212-229
Number of pages18
JournalCurrent Problems in Obstetrics, Gynecology and Fertility
Issue number6
StatePublished - Nov 2002

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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